<template>
  <div class="type-nav">
    <!-- 事件委派 -->
    <div class="container" @mouseleave="leaveShowCurrenIndex" @mouseover="showSort">
      <h2 class="all">全部商品分类</h2>
      <nav class="nav">
        <a href="###">服装城</a>
        <a href="###">美妆馆</a>
        <a href="###">尚品汇超市</a>
        <a href="###">全球购</a>
        <a href="###">闪购</a>
        <a href="###">团购</a>
        <a href="###">有趣</a>
        <a href="###">秒杀</a>
      </nav>
      <!-- 添加过渡动画 -->
      <transition name="sort">
        <!-- 三级联动 -->
        <div class="sort" v-show="isShowSort">
          <!-- 事件委派 -->
          <div class="all-sort-list2" @click="goSearch">
            <div class="item bo" v-for="(c1, index) in categoryList" :key="c1.categoryId" :class="{ skyblue: index === currenIndex }" @mouseover="passCurrenIndex(index)">
              <h3>
                <a :data-categoryname="c1.categoryName" :data-category1id="c1.categoryId">{{ c1.categoryName }}</a>
              </h3>
              <div class="item-list clearfix" :style="{ display: currenIndex === index ? 'block' : 'none' }">
                <div class="subitem" v-for="c2 in c1.categoryChild" :key="c2.categoryId">
                  <dl class="fore">
                    <dt>
                      <a :data-categoryname="c2.categoryName" :data-category2id="c2.categoryId">{{ c2.categoryName }}</a>
                    </dt>
                    <dd>
                      <em v-for="c3 in c2.categoryChild" :key="c3.categoryId">
                        <a :data-categoryname="c3.categoryName" :data-category3id="c3.categoryId">{{ c3.categoryName }}</a>
                      </em>
                    </dd>
                  </dl>
                </div>
              </div>
            </div>
          </div>
        </div>
      </transition>
    </div>
  </div>
</template>

<script>
import { mapState, mapActions } from 'vuex'
// 引入lodash模块
// 按需引入
import throttle from 'lodash/throttle'
export default {
  name: 'TypeNav',
  data() {
    return {
      currenIndex: -1,
      // 默认显示三级分类
      isShowSort: true,
    }
  },
  mounted() {
    // 放在这里请求次数会增多，性能较差
    // this.$store.dispatch('homeStore/getCategoryList')
    // 若跳转到search路由则三级分类隐藏
    if (this.$route.path === '/search') {
      this.isShowSort = false
    } else {
      this.isShowSort = true
    }
  },
  computed: {
    ...mapState('homeStore', { categoryList: 'categoryList' }),
  },
  methods: {
    // 使用lodash的节流throttle函数(别用箭头函数),使得每次操作都能触发
    passCurrenIndex: throttle(function (index) {
      this.currenIndex = index
    }, 10),
    // 若不是home路由三级分类列表隐藏，并离开时取消背景颜色
    leaveShowCurrenIndex() {
      if (this.$route.path !== '/home') {
        this.isShowSort = false
      }
      this.currenIndex = -1
    },
    // 进入显示三级分类列表
    showSort() {
      this.isShowSort = true
    },
    // 三级分类跳转Search路由
    goSearch(e) {
      // console.log(e.target.dataset)
      let { categoryname, category1id, category2id, category3id } = e.target.dataset
      // 拆分push里面的配置对象
      let location = { name: 'sousuo' }
      let query = { categoryname }
      // 先判断是否是有自定义属性data-categoryname的a标签
      if (categoryname) {
        // 判断为几级分类
        if (category1id) {
          //一级
          query.category1id = category1id
        } else if (category2id) {
          // 二级
          query.category2id = category2id
        } else {
          // 三级
          query.category3id = category3id
        }
        // 最后合并参数
        // 如果有params，就和query合并
        if (this.$route.params) {
          location.query = query
          location.params = this.$route.params
          this.$router.push(location)
        }
      }
    },
  },
}
</script>

<style lang="less" scoped>
.type-nav {
  border-bottom: 2px solid #e1251b;

  .container {
    width: 1200px;
    margin: 0 auto;
    display: flex;
    position: relative;

    .all {
      width: 210px;
      height: 45px;
      background-color: #e1251b;
      line-height: 45px;
      text-align: center;
      color: #fff;
      font-size: 14px;
      font-weight: bold;
    }

    .nav {
      a {
        height: 45px;
        margin: 0 22px;
        line-height: 45px;
        font-size: 16px;
        color: #333;
      }
    }

    .sort {
      position: absolute;
      left: 0;
      top: 45px;
      width: 210px;
      height: 461px;
      position: absolute;
      background: #fafafa;
      z-index: 999;
      .all-sort-list2 {
        .item {
          h3 {
            line-height: 30px;
            font-size: 14px;
            font-weight: 400;
            overflow: hidden;
            padding: 0 20px;
            margin: 0;

            a {
              color: #333;
            }
          }

          .item-list {
            position: absolute;
            width: 734px;
            min-height: 460px;
            background: #f7f7f7;
            left: 210px;
            border: 1px solid #ddd;
            top: 0;
            z-index: 9999 !important;

            .subitem {
              float: left;
              width: 650px;
              padding: 0 4px 0 8px;

              dl {
                border-top: 1px solid #eee;
                padding: 6px 0;
                overflow: hidden;
                zoom: 1;

                &.fore {
                  border-top: 0;
                }

                dt {
                  float: left;
                  width: 54px;
                  line-height: 22px;
                  text-align: right;
                  padding: 3px 6px 0 0;
                  font-weight: 700;
                }

                dd {
                  float: left;
                  width: 415px;
                  padding: 3px 0 0;
                  overflow: hidden;

                  em {
                    float: left;
                    height: 14px;
                    line-height: 14px;
                    padding: 0 8px;
                    margin-top: 5px;
                    border-left: 1px solid #ccc;
                  }
                }
              }
            }
          }
        }
        .skyblue {
          background-color: skyblue;
        }
      }
    }

    .sort-enter {
      height: 0;
    }
    .sort-enter-to {
      height: 461px;
    }
    .sort-enter-active {
      transition: all 0.5s;
    }
 /*    .sort-leave {
      height: 0;
    }
    .sort-leave-to {
      height: 461px;
    }
    .sort-leave-active {
      transition: all 0.5s;
    } */
  }
}
</style>